Am I pregnant or should I be expecting my period soon?

Glow showed that my period was supposed to start 2 weeks ago. But my periods are very far apart (46 days) so i manually moved it back and so i should have started today. Yesterday I spotted blood. I took 2 clear blue pregnancy tests and both came back negative. I still haven't gotten my period. I'm going to take more tests later on. I'm really young so my periods are really irregular and yesterday I did take Vitamin C to try and bring on my period. I'm not cramping like I normally do either. What are your thoughts?